bug#16026: Connection specific settings and proxies

[Lars Ingebrigtsen <larsi@gnus.org>]

Michael Albinus <michael.albinus@gmx.de> writes:

>> It's easy to create an ad-hoc system just for network timeout
>> parameters, like I did with many GnuTLS parameters early on, but the
>> systematic approach Michael gave us is much better. The only reason I
>> haven't implemented it is lack of time.
>
> If I could help, just ping me. Not that I have too much free time, but
> I'm interested in this.

I was just pondering something that's perhaps related: HTTP proxying in
the with-url branch.

url.el uses an alist on the form ((("http" . "foo.bar:port")
"proxy:port")) or something to determine what connections should be
proxied.  It doesn't support HTTPS proxies (i.e., "CONNECT"), so it's
rather underspecified, if I read the code correctly.

I'm also not sure what level to put the proxies on: Should they be
passed in from the application (i.e., eww, Gnus, etc) or should it be a
global Emacs setting?

If the latter, you could see having a call like

(set-proxy :match-domain ".*\\.foo\\.bar\\'"
           :target-port 443
           :proxy-server "localhost"
           :proxy-port 80
           :method 'connect)

to set up the proxy.  (Well, really, you'd have a mode that would allow
you to tweak the global proxy setup.)

Now, this all kinda ties in with what Ted was talking about: A
per-connection setting thing.  So you could envision doing just the same
with, say, IMAP, if you need to have that be proxied or something, and
then it turns out that the right layer for this stuff is probably in
`open-network-stream': Almost all networking already goes through that
function, so by implementing it there, all clients get automatic proxy
support.

The same mechanism for determining things like lifecycle settings (i.e.,
network timeout parameters) could somehow be squeezed in here.

But I've read the doc for connection-local-set-class-variables, and I
don't quite see how to match up these needs with that mechanism...

And, like I said, I don't know whether it's the right design choice to
have these settings be global, or whether they should be passed in
explicitly from each application.  Would users want to use one set of
proxies while reading HTML news from Gnus and another when reading from
eww?  Perhaps?  Perhaps not?

So many options...

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no